Nuclears lifetime cost per KwH isn't cheap, and that's the main reason it hasn't been mass implemented.

The upfront cost is simply too much for the amount of energy it produces.*

But solar and wind are the two cheapest sources of energy available, we need more energy stores to go fully solar and wind. We don't really have enough mountains, to rely fully on hydro energy by pumping water up a hill with excess energy - But it's a start, Sweden is minting money on this strategy.

Battery technology however seems to be evolving rapidly at the moment, there's a serious hope we'll end up with batteries as base loaders in two decades - One big issue, is how to ensure no need for a way larger energy grid capacity than necessary, but people are working on ways to introduce battery farms locally at wind and solar farms. So they'd pass the excess energy over there, rather than through the grid

*My information might be outdated, as I'm not aware if the SMRs if proven capable, are cheaper today than the calculations I've seen my mate do for a bachelor projects of economics just short of a decade ago